1. Field of the Invention
The present invention relates to a method for sealing fenestration openings in buildings using a spray-on coating.
2. Description of Related Art
Fenestration openings in buildings are a particularly challenging portion of a structure to seal from water penetration. Sealing fenestration openings generally requires sealing gaps and cracks at joints between building elements (for example, where one framing element buts up against another framing element) as well as sealing over the entire framework prior to inserting a window or door into the opening. Complete protection of the fenestration opening further requires application of flashing materials over the seam between the window or door and the building frame around the fenestration opening in which the window or door resides and sealing of that flashing material with the building frame. Proper sealing of a fenestration opening can be a time consuming process that adds significant cost to constructing a building.
The process of sealing fenestration openings has become easier with the innovation of liquid waterproofing membrane materials and liquid flashing materials. Liquid waterproofing membrane materials offer convenience of efficiently and completely coating and sealing a surface with a material that adheres to a surface to seal that surface. Unlike conventional sheet-type house-wrap materials, liquid waterproofing membranes will not blow off in the wind or allow moisture to penetrate between the house-wrap sheet and building frame during construction. Moreover, a single person can easily apply liquid waterproofing membranes to a structure. Peel and stick adhesive-backed flashing is also an option for sealing a fenestration opening before, after, or both before and after inserting a window or door into the opening. Peel and stick products offer improvements in handling over sheet-type house-wrap materials, but still require undesirable amounts of time to cut the product to size, peel off and dispose of the backing sheet followed by positioning and applying the product to the building structure.
Commercially available liquid waterproofing membranes include Protecto LWM200™ from Protecto Wrap Company, StoGuard™ brand waterproofing/air barrier assembly from Sto Corporation and Dribond Liquid Flash water proofing membrane. While these liquid waterproofing membranes offer an advantage over conventional sheet-type house-wrap materials and peel and stick flashing products, they still leave room for improvement.
Dribond Liquid Flash is a liquid sealant material that is designed to be brushed onto a surface to form a resilient waterproof flashing membrane. Brushing a liquid membrane onto a building frame is easier than applying sheet-type house-wrap or a peel and stick flashing product and provides more intimate adhesion and a better seal between the membrane and frame. However, it is desirable to have a sprayable liquid sealing material to make application even more efficient, as well as more uniform, than brushing. However, achieving a sprayable liquid sealing material that has the sealing and coating properties of a more viscous brushable membrane material is challenging to achieve since sealing properties are enhanced by higher viscosity and sprayability by lower viscosity. Hence, to achieve suitable sealing properties most liquid membrane materials are only available in brushable form, or must be combined with additional sealing materials.
Protecto LWM200 is another liquid sealant material specifically for window and door openings. While advertising literature indicates that a spray applied version of LWM200 Liquid Waterproofing Membrane is available upon request, yet the present inventors have been unable to obtain any sprayable version despite making such a request from the manufacturer. According to its literature LWM200 Liquid Waterproofing Membrane is limited in its ability to span gaps and cracks to gaps and cracks up to 1/16th of an inch (1.6 millimeters). Larger gaps and cracks require first application of a separate sealant or patch material to fill or cover the gap/crack followed by subsequent application of the liquid sealant material. Therefore, even if a spray version of Protecto LWM200 were available it would be a desirable improvement to have a sprayable membrane that could span gaps and cracks greater than 1/16th inch without requiring additional sealants or patches. Spanning a gap or crack greater than 1/16th inch requires a relatively high viscosity material, which makes spraying the material a greater challenge. Hence, obtaining sprayability with an ability to span gaps greater than 1/16th of an inch is a particular challenge.
StoGuard also comprises a sprayable liquid membrane material but specifically requires additional protection for joints in the surfaces being coated. In particular, installation instructions for StoGuard instruct applying mesh to vertical and horizontal sheathing joints prior to applying any sprayable coatings. Moreover, the installation instructions specify applying two more coatings after the mesh: spraying or trowling Sto Gold Fill™ over the mesh and fasteners and then, after that dries, application of Sto Gold Coat™ over the wall surface. Instructions for window and door openings also specify application of mesh to joints and seams in rough opening frames followed by application of both Sto Gold Fill and Sto Gold Coat to complete the protective coating. Additional mesh, Sto Gold Fill and Sto Gold Coat are all needed to flash a window once installed in the opening
Applying additional materials to seams and joints takes time and therefore increases construction costs. The cost of applying additional materials is particularly challenging for recessed windows and/or windows having complex shapes. Recessed windows tend to have deep fenestration openings with large surface areas in the building framework defining the fenestration opening. Complex shaped fenestration openings, such as arched openings or even more complex shapes, can comprise a multitude of joints and seams in the building frame defining the fenestration opening. Increasing the surface areas and increasing the number of seams and joints in the framework within a fenestration opening increases the amount of labor needed to apply sealing materials and, hence increases the cost of constructing the building. Therefore, it is desirable to reduce the number of different sealing materials needed to seal a fenestration opening. It is also desirable to have a spray on sealing material to increase the speed at which the material can be applied relative to painted, troweled or gunned (that is, application by a caulk gun) materials.
It is desirable to be able to spray apply sealing materials to seal fenestration openings, including gaps and cracks greater than 1/16th inch, without requiring additional sealing materials. It is further desirable to be able to spray apply a sealing material to flash windows that have been inserted into a fenestration opening without first having to apply additional flashing material, or preferably, any additional flashing material before or after applying the sprayable waterproofing membrane material.